Alternanthera reineckii 'rosaefolia'

The purple color underneath Alternanthera reineckii 'roseafolia' leaves provides an effective contrast to the many green plants in an aquarium particularly when planted in groups. Three to five strong specimens can be used for the background area to help accent the shades of green aquarium plants. Although uncommon in Nature Aquarium layout designs, this is the most popular red plant used in Dutch style aquariums.

This plant, unlike most other red plants, prefers rich conditions with high nitrates (10 ppm or more) and high phosphate (0.5 ppm or more). If grown under lean conditions under very high light, substrate fertilization placed at the roots will greatly enhance growth and overall health.

Family: Amaranthaceae
Genus: Alternanthera
Region: Central/South America
Location: Argentina, Paraguay, Brazil

More info:
http://www.aquaticplantcentral.com/forumapc/plantfinder/details.php?id=58